With multi-core cable, core connections have been made in practice, for example, by offsetting or penciling the core insulations, applying the core connector, wrapping with high voltage insulation tapes, applying an electrically conductive outer shielding, and filling the splice case or enclosure with insulating material. The wrapping of the insulating tapes has to be performed with care while keeping to relatively close dimensional tolerances to obtain the desired stress control. With single core cable connections, this does not normally cause any particular difficulties. With multi-core cable connections, however, when wrapping the insulation tape, the other cores must be worked around. Relatively long end portions of the cores have to be exposed to permit spreading the cores apart far enough to permit the winding to be performed with the necessary accuracy. But often, in cable manholes, there is little cable length available to make the connection; in that case only relatively short end portions of the cores may be exposed, and the winding is very difficult, and often inaccurate.
There are other types of core connections known in which the stress control shielding consists of a prefabricated sleeve-like elastomeric body which, similar to the above-described outer splice case, may be kept in readiness on one of the core ends to be connected and after the conductor connector has been applied, may be pushed over the connection area into a position in which it extends from core insulation to core insulation being seated thereon in sealed relationship. Such prefabricated elastomeric bodies may include an electrically conductive cylindrical lining and an external conductive coating, so that the lining will form an equipotential area in contact with the connector, and the conductive coating may be connected to the protecting layers of the two core ends as disclosed in U.S. Pat. No. 3,485,935. When using these known core connections for making the overall cable connection of multi-core cables, at least one core end must be so long that the elastomeric body may be pushed therealong into a position in which the spreading apart of the core ends as much as necessary and the fitting of the conductor connectors are not obstructed. In most applications the space required for this is not available in the longitudinal direction of the cable, because medium voltage multi-core cables are mainly used as buried cables for 12 to 20 kV 3-phase current power supply mains, for example in densely populated areas. It has, therefore, been necessary in this principal field of application to use the above-described tape wrapping technique, although this is particularly difficult, particularly in restricted spaces.